1. Field of Invention
This invention relates generally to the field of threaded fasteners or thread clamping devices, and more particularly to a thread clamping device capable of internally measuring the tension load on the device and capable of remotely reporting the measured load and a unique identification code electronically, typically employing RFID (Radio Frequency Identification) technology.
2. Description of the Prior Art
The fastener industry has several examples of threaded female fasteners with moving segments that facilitate quick connection or assembly of the fastener to a threaded rod when assembled in one direction (moved along the threaded rod), but locks when linear motion (without rotation) of the fastener along the threaded rod is attempted in the opposite direction. That is, the fastener can be moved along a threaded rod in one direction rapidly and without rotation (hereinafter the “ratcheting” direction), but locks when motion is attempted along the rod in the opposite direction (hereinafter the “locking” direction), requiring rotation of the fastener to move the fastener in the locking direction. Upon applying an external torque to tighten the fastener, the fastener will drive its segments tightly against the threaded rod (if the fastener base can rotate), but not move axially along the rod, thus providing locking friction between the segment threads and the rod threads.
However, existing fasteners generally lack the capability to measure the actual load on the fastener and then communicate the measured load value to a remote receiving station. {Note: It is normal procedure to communicate to the remote receiving station an identifier that specifies which fastener generated the transmitted data along with such data. This is to be understood in the following descriptions even though an explicit recitation of transmitted identifier may not be provided in all cases.} When received by a remote receiving station, such information would be useful for several purposes including ascertaining if the fastener is bearing the proper load, not so large as to threaten failure nor so small as to imply improper installation or some other defect in the utilization of the fasteners.
It is common for fasteners to be installed with a torque wrench capable of applying a known and specified amount of torque to the fastener during installation, but this does not directly determine the actual load on the fastener during service. In particular, information about changes in the actual load experienced by the fastener during its service life, whether arising from wear on this or another component part or another cause, is unknown. Thus, a need exists in the art for devices and procedures for the in-service determination and communication of the load being born by a thread clamping device in service on a threaded rod.